The present disclosure relates to a light conversion member using quantum dots, and a backlight unit and a device including the same, and more particularly, to a light conversion member having excellent reliability, quantum efficiency, and white balance characteristics, and a backlight unit and a device including the same.
Recently, with the development of information technology, display technologies also have been rapidly developed. Accordingly, flat panel display (FPD) devices having advantages in term of thinness, light weight, and low power consumption, which include liquid crystal display (LCD) devices, plasma display panel (PDP) devices, electroluminescence display (ELD) devices, field emission display (FED) devices, and the like, have been developed and have replaced conventional cathode ray tubes (CRTs).
Among these devices, liquid crystal display devices have attracted attention as a next generation advanced display device which is characterized by low power consumption, good portability, highly integrated technology, and highly added value.
The liquid crystal display device is not self-luminescent, but a photoreceptive type display device which displays images by light incident from the outside, so that a light source is essentially required. Conventionally, cold cathode fluorescent lamps (CCFLs) have been mainly used as a light source of the liquid crystal display device. However, the cold cathode fluorescent lamps have shortcomings in terms of luminance uniformity and color purity if the liquid crystal display device is large-sized.
Therefore, instead of the cold cathode fluorescent lamp, tri-color light-emitting diodes (LEDs) are being recently used as a light source of the liquid crystal display device. When tri-color light-emitting diodes are used as a light source, there are advantages in that high quality images may be realized due to reproducible high color purity, but manufacturing costs disadvantageously increase because tri-color light-emitting diodes are very expensive. Techniques for remedying these shortcomings have been proposed, in which a relatively inexpensive blue light-emitting diode is used as a light source and white light is realized by converting blue light into red light and green light using a light conversion film including quantum dots (QDs).
Meanwhile, quantum dots are easily oxidized by moisture, oxygen, and heat. Accordingly, currently proposed light conversion films are generally manufactured in such a way that a barrier film for preventing permeation of moisture and oxygen is attached on upper and lower surfaces of the light conversion film. However, these conventional light conversion films do not include a separate barrier unit on the sides thereof, so that problems such as quantum dot oxidation by oxygen or moisture permeating through the sides of the film still occur, thereby resulting in reliability degradation due to moisture or heat when the light conversion film is applied to a backlight unit. In order to solve these problems, methods for increasing quantum dot density in the light conversion film are being considered. However, when the quantum dot density in the light conversion film increases, the proportion of red light and/or green light converted by quantum dots also increases. As a result, RGB color balance is broken, which causes a change in white color coordinates.